Amfibian sometimes

sometimes I'm a step ahead, but think I'm two behind
sometimes I get wound more tightly trying to unwind
sometimes I am quite impressed by simple things you do
sometimes I am quite a mess, but all because of you
on a summer's day I get an awful chill
after just one sip I know I've drunk my fill
you think that I'm the prey but you're the one who's caught
in spite of what you say, I know your every thought
sometimes in the bright day sun a darkness shades my sight
sometimes I can see for miles in the blackest night
sometimes though you never see I watch you for a while
sometimes though it just can't be I think I see you smile